This invention relates generally to the pivotal axis of a tailgate for use on a truck or trailer bed and, more particularly, to those beds recessed between tires and fenders commonly referred to as low profile.
Tailgates have been designed to pivot about vertical, horizontal or combinations of these axes and all include means for locking them in a closed position. Pickup truck full width tailgates typically only pivot about a lower edge transverse axis. A low profile trailer may also have a tailgate that pivots about a lower edge transverse axis so that the tailgate can serve as a loading ramp. Enclosed low profile trailers, such as horse trailers, often have three piece tailgates with the upper portion divided into nearly equal left and right segments that each open about a vertical laterally outboard axis. They can be swung and secured in longitudinal positions above the fenders. The lower tailgate portion pivots about a horizontal lower edge axis to serve as a loading ramp.
Dump trailers typically have a bed that is equipped with a fixed headboard and sides about two feet in height. Selections of three alternate tailgates are often offered. A tailgate type equal in height to the sides and referred to as barn doors, divides the tailgate into nearly equal left and right segments that each open about a vertical laterally outboard axis. Another similar height tailgate can be selectively pivoted about horizontal top or bottom edge axes. When pivoted about the upper axis, chains are often used to limit the tailgate opening for spreading a load as the bed is raised while traveling forward. The same tailgate, also restrained by chains, can be selectively pivoted about a horizontal lower edge axis to align with and therefore extend the load surface rearward. Some tailgates combine the features of both of the above types. A third type, sometime referred to as a landscape tailgate, is much taller and allows selection between two lateral pivot axes. The upper axis is usually located above the elevation of the bed sides but below the top of the tailgate. This axis is supported by extended bed corner posts. The lower pivot axis is located at the lower edge of the tailgate. This tailgate functions like the preceding tailgate, except that it can be pivoted about the lower axis to act as a loading ramp or the upper axis for dumping bulky materials. A trailer equipped to selectively tilt or dump, as taught by Pat. No. RE41126, could be equipped with any of these tailgates.
When the beds of open trucks or trailers are empty and their tailgates are closed, transport wind resistance is increased and fuel economy suffers. When pivoted horizontal about a lateral axis, tailgates lengthen trucks or trailers and can create parking or storage issues. Transport width can't be achieved when fully opened vertical axis barn door type tailgates strike the fenders of low profile work beds.
It would be desirable to provide a tailgate pivot system that allowed either a full width or divided tailgate to be swing to a longitudinal position beside the bed of a truck or low profile trailer. It would also be desirable that in this position the tailgate could be secured. It would also be desired that in this position the tailgate or its support system wouldn't increase transport width. It would also be desired that in this position transport wind resistance could be reduced. It would also be desired that the same tailgate could selectively pivot about a lower lateral axis for bed extension or for use as a loading ramp. It would also be desired that, when used on a dumping bed, this tailgate could selectively pivot about an upper lateral pivot axis for spreading loose materials as the bed travels forward while being raised.